Ceramic sprayed member-cleaning method

Abstract

A ceramic sprayed member-cleaning method which is capable of reliably suppressing desorption and attachment of water. The surface of a ceramic sprayed member and water are chemically bonded to each other, whereby the water is stabilized. Water physically adsorbed on the surface of the ceramic sprayed member is desorbed.

1. A method of cleaning a ceramic sprayed member having a predetermined ceramic material thermally sprayed on a surface thereof, comprising:
 a stabilizing step of chemically bonding the surface of the ceramic sprayed member and water to each other to stabilize the water; and 
 a desorbing step of desorbing water physically adsorbed on the surface of the ceramic sprayed member, wherein said stabilizing step includes carrying out hydration processing in which the ceramic sprayed member is exposed to a temperature range of 100° C. to 300° C., a pressure not lower than 202.65 kPa, and a relative humidity not lower than 90%, and 
 wherein in said desorbing step, a gas highly reactive with water is introduced into a space surrounding the ceramic sprayed member, and the introduced gas is selected from the group consisting of a methylsilane compound being trimethylchlorosilane, dimethyldichlorosilane, monomethyltrichlorosilane, or tetrachlorosilane, and a water-reactive oxygen/halogen compound being dichloropropane, dibromopropane, nitrosyl chloride, carbonyl chloride (phosgene), carbonyl fluoride, diborane, chlorine, fluorine, thionyl bromide, iodomethyl propane, acetyl chloride, acetone dimethyl acetal, carbon monoxide, hydrogen chloride, or trichloroboron. 
 
     
     
       2. A method as claimed in  claim 1 , wherein said stabilizing step comprises forming a layer mainly composed of a hydroxide of ceramic on the surface of the ceramic sprayed member. 
     
     
       3. A method as claimed in  claim 1 , wherein said desorbing step comprises heating the ceramic sprayed member. 
     
     
       4. A method as claimed in  claim 1 , further comprising a removing step of removing deposits attached to the ceramic sprayed member, before execution of said stabilizing step. 
     
     
       5. A method as claimed in  claim 4 , wherein said removing step comprises at least soaking of the ceramic sprayed member in an organic solvent or acid. 
     
     
       6. A method as claimed in  claim 1 , wherein the ceramic material comprises a rare earth metal oxide. 
     
     
       7. A method as claimed in  claim 6 , wherein the rare earth metal oxide comprises yttria.